Vision-assisted robotized depalletizer

Abstract

A vision-assisted robotized depalletizer receives at a pallet station a pallet loaded with products and outputs on a conveyor unitized products aligned in a desired orientation. Such depalletizers include a vision system having one or more image acquisition sensors that are positioned relative to the pallet station so as to have a field of view covering a top portion of the pallet. The sensors send to a controller one or more image of the top portion of the pallet that the controller uses along to determine the position of each product in the top portion of the pallet. The depalletizer further includes a robot equipped with a depalletizing tool that is coupled to the vision system controller for receiving information indicative of the position of each product from the top portion and uses that information to pick and position on the output conveyor each product from the top portion.

What is claimed is: 
     
       1. A depalletizer comprising:
 a pallet unloading station for receiving a pallet of products; 
 a vision system for generating at least one image of a top portion of the pallet received at the pallet station, the vision system effecting determination, based on the at least one image, of the position of at least one product in the top portion of the pallet; and 
 a robot equipped with a depalletizing tool, the robot being configured for receiving information from the vision system indicative of the position of the at least one product from the top portion and being configured to pick and position on an output surface said each product, so as to effect removal of each product from the top portion, based on the received information; 
 wherein the vision system is configured so as to generate the at least one image of the top portion of the pallet received at the pallet station, where the vision system effects determination, based on the at least one image, of the position of each product in the top portion of the pallet and the robot receives information identifying the determined position of each product, based on the at least one image, so that the robot motion between picks and positions on the output surface of each product in the removal of each product, effected via the robot picks and positions, is substantially independent of generation of the at least one image by the vision system. 
 
     
     
       2. The depalletizer of  claim 1 , wherein the vision system includes at least one image acquisition sensor. 
     
     
       3. The depalletizer of  claim 2 , wherein the vision system includes a vision system controller coupled i) to the at least one image acquisition sensor for receiving the at least one image therefrom and ii) to the robot controller for sending thereto the information indicative of the position of said each product from the top portion. 
     
     
       4. The depalletizer of  claim 3 , wherein said determining the position of said at least one product is achieved by the controller analysing at least one of the following characteristics from the at least one image: edges of the at least one product seen on the at least one image, corners of the at least one product seen on the at least one image, and pattern repetition of the at least one product seen on the at least one image. 
     
     
       5. The depalletizer of  claim 3 , wherein said determining the position of said at least one product is achieved by the controller analysing at least one of depth and intensity variations of the at least one image. 
     
     
       6. The depalletizer of  claim 3 , wherein the vision system controller further uses at least one characteristic of the at least one product, that is determined independent of the at least one image, along with said at least one image in determining the position of said at least one product from the top portion of the pallet. 
     
     
       7. The depalletizer of  claim 6 , wherein the at least one characteristic of the at least one product includes at least one of i) a dimension of the at least one product and ii) a type of the at least one product. 
     
     
       8. The depalletizer of  claim 2 , wherein the at least one image acquisition sensor includes at least one of a gray tone camera, a colour camera, a laser triangulation scanner, a structured light type sensor, a stereoscopy sensor, and time-of-flight type sensor. 
     
     
       9. The depalletizer of  claim 2 , wherein the at least one image acquisition sensor is positioned above the pallet unloading station. 
     
     
       10. The depalletizer of  claim 2 , wherein the at least one image acquisition sensor includes a plurality of sensors. 
     
     
       11. The depalletizer of  claim 1 , wherein the output surface is a surface of at least one conveyor. 
     
     
       12. The depalletizer of  claim 1 , wherein the pallet unloading station is a surface of a conveyor. 
     
     
       13. The depalletizer of  claim 1 , wherein the products include one of closed cartons, totes, open top cartons, trays bags and pouches. 
     
     
       14. The depalletizer of  claim 1 , wherein the robot is a four (4) or six (6) axis articulated robot arm. 
     
     
       15. The depalletizer of  claim 1 , wherein the robot is a gantry-type robot system. 
     
     
       16. The depalletizer of  claim 1 , wherein the depalletizing tool includes at least one of a suction cup, a suction pad, a support plate and support fingers. 
     
     
       17. The depalletizer of  claim 1 , wherein the depalletizing tool is part of a series of depalletizing tools, each mountable via a tool changer and being adapted to a specific type of products. 
     
     
       18. The depalletizer of  claim 1 , wherein the vision system further uses the at least one image for detecting a slip sheet in the pallet; the depalletizer further comprising a slip-sheet removing device coupled to the vision system for removing the slip sheet. 
     
     
       19. The depalletizer of  claim 18 , wherein the slip-sheet removing device is part of the depalletizing tool. 
     
     
       20. The depalletizer of  claim 1 , wherein the pallet unloading station includes of a pallet elevator that lifts the pallet of products as it is depalletized. 
     
     
       21. The depalletizer of  claim 1 , wherein the determined position is decoupled from both robot motion and vision system traverse relative to the top portion of the pallet. 
     
     
       22. A depalletizer comprising:
 a vision system including at least one image acquisition sensor for generating an image of a top portion of a pallet positioned under the at least one image acquisition system, and a vision system controller coupled to the at least one image acquisition sensor for receiving the image, the vision system effecting determination, based on the image, of the position of at least one product in the top portion of the pallet; and 
 a robot equipped with a depalletizing tool including at least one suction means, the robot being configured for receiving information from the vision system indicative of the position of the at least one product from the top portion and being configured to pick and position on an output conveyor said each product, so as to effect removal of each product from the top portion, based on the received information; 
 wherein the vision system is configured so as to generate the image of the top portion of the pallet positioned under the at least one image acquisition system, and where the vision system effects determination, based on the image, of the position of each product in the top portion of the pallet and the robot receives information identifying the determined position of each product, based on the at least one image, so that the robot motion between picks and positions on the output surface of each product in the removal of each product, effected via the robot picks and positions, is substantially independent of generation of the at least one image by the vision system. 
 
     
     
       23. The depalletizer of  claim 22 , wherein the determined position is decoupled from both robot motion and vision system traverse relative to the top portion of the pallet. 
     
     
       24. A method for depalletizing a pallet of products, the method comprising:
 generating, with a vision system, an image of a top portion of the pallet; 
 effecting determination, with a controller, based on the image, of at least one product to pick from the top portion of the pallet; 
 receiving, with a robot, information indicative of the position of the product to pick on the pallet from the controller; and 
 moving the robot with respect to the top portion of the pallet and picking, with the robot, the product and moving the product on an output surface so as to effect a removal of each product from the top portion; 
 wherein generating the image of the top portion of the pallet with the vision system, the robot receives information identifying the determined position of each product, based on the at least one image, so that the robot motion between picks and positions on the output surface of each product in the removal of each product, effected via the robot picks and positions, is substantially independent of generation of the image of the top portion by the vision system. 
 
     
     
       25. A method as recited in  claim 24 , further comprising:
 inputting in a controller information about the products; and 
 the controller further using the information about the products along with the image to determine the position of the product to pick from the top portion of the pallet. 
 
     
     
       26. A method as recited in  claim 24 , wherein effecting determination, with a controller, based on the image, of a product to pick from the top portion of the pallet is decoupled from both moving the robot and moving the vision traverse with respect to the top portion of the pallet.